One-time dry dust removal system for ultra-clean converter

Abstract

The utility model discloses a one-time dry dust removal system for an ultra-clean converter. The one-time dry dust removal system comprises a high-effect heat exchanger, a rotational flow heat recovery device, an electrostatic dust remover, a high-temperature-resistant explosion-proof ultra-clean dust remover, a cooling replacement fan, a clean gas pipe, a gas axial flow fan and a gas washing dehydrator, a converter sequentially passes through a high-efficiency heat exchanger and a rotational flow heat recovery device and then enters an electrostatic dust collector and / or a high-temperature-resistant explosion-proof ultra-clean dust collector to form clean coal gas, the concentration of an outlet of the ultra-clean dust collector can be kept stable below 5mg / Nm < 3 >, and then the clean coal gas is washed and cooled through a coal gas axial flow fan and a coal gas cooling dehydrator and then is conveyed to a coal gas switching station. Conveying the qualified coal gas to a coal gas cabinet; unqualified coal gas is sent to a diffusion chimney to be ignited and diffused.

Description

TECHNICAL FIELD

[0001] The utility model discloses a kind of ultra-clean converter primary dry method dust removal systems, and it is related to environmental protection equipment field. BACKGROUND

[0002] At present, the converter of steel enterprise new building and reconstruction mostly adopts dry method dust removal system, such as the improved converter primary flue gas dry method dust removal system provided in Chinese document CN216274225U, including evaporative cooler, the output end of evaporative cooler is connected with electric dust collector, the output end of electric dust collector is connected with fan, the output end of fan is connected with silencer, the output end of silencer is connected with high-efficiency cooling demisting tower, the output end of high-efficiency cooling demisting tower is connected with switching station, the output end of switching station is connected with ignition dispersion tower, the document adopts evaporative cooler to cool down, generally flue gas temperature is directly reduced from 900 DEG C to about 250 DEG C, and heat is not recycled.

[0003] The existing converter primary dry method dust removal system adopts electrostatic precipitator process, and the following problems exist: when electrostatic precipitator is overhauled, the phenomenon of smoke from the dispersion chimney will be caused; in addition, due to the different degrees of discharge of high-voltage power supply, the voltage and current between the polar line and the polar plate will also fluctuate greatly, which will affect the dust removal efficiency of the electrostatic precipitator, and the dust emission concentration at the outlet of the dispersion chimney will fluctuate greatly. INVENTION CONTENTS

[0004] In view of the deficiencies of the prior art, the present utility model provides an ultra-clean converter primary dry method dust removal system, which recycles high-quality heat energy by using a high-efficiency heat exchanger and a heat recovery device, and the outlet concentration of the dust remover can be maintained at a stable 5mg / Nm 3 The following.

[0005] To achieve the above-mentioned purpose, the utility model is realized by the following technical solutions:

[0006] An ultra-clean converter primary dry method dust removal system, comprising a high-efficiency heat exchanger, a banana bend separator, a cyclone heat recovery device, a water-cooled chain conveyor, a raw gas pipe, an electrostatic precipitator, a high-temperature-resistant explosion-proof ultra-clean dust remover, a cooling replacement fan, a clean gas pipe, a gas axial flow fan and a gas washing dehydrator.

[0007] The inlet of the high-efficiency heat exchanger is connected with the converter through a vaporization cooling flue, the raw gas of the converter enters the high-efficiency heat exchanger for heat recovery, a banana bend dust remover is arranged between the high-efficiency heat exchanger and the cyclone heat recovery device, and a water-cooled chain conveyor is arranged at the bottom of the banana bend dust remover for capturing and conveying coarse ash.

[0008] The output end of the cyclone heat recovery device is connected with the electrostatic precipitator and / or the high-temperature-resistant explosion-proof ultra-clean dust remover through the raw gas pipe.

[0009] The output end of the high-temperature-resistant explosion-proof super-clean dust collector is connected to a clean gas pipe, and the gas in the clean gas pipe is washed and cooled by a gas axial flow fan and a gas cooling dehydrator, and then sent to a gas switching station. The qualified gas is sent to a gas tank through detection, and the unqualified gas is sent to a dispersing chimney for ignition and dispersion.

[0010] Further, the electrostatic precipitator and the high-temperature-resistant explosion-proof super-clean dust collector can work in series, or the high-temperature-resistant explosion-proof super-clean dust collector can work alone. The first metal hard seal butterfly valve and the first explosion-proof mirror valve are arranged at the inlet main pipe of the electrostatic precipitator, and the second metal hard seal butterfly valve and the second explosion-proof mirror valve are arranged at the outlet main pipe of the electrostatic precipitator.

[0011] The third metal hard seal butterfly valve and the third explosion-proof mirror valve are arranged at the inlet main pipe of the high-temperature-resistant explosion-proof super-clean dust collector.

[0012] Further, the outlet temperature of the gasification cooling flue is 750-850℃, and after the high-efficiency heat exchange of the gas and water in the high-efficiency heat exchanger, the high-quality heat in the raw coal gas is efficiently recovered, and the temperature is reduced to 600℃, and the raw coal gas enters the banana bend dust collector. The banana bend dust collector is provided with a plurality of baffles, and the inlet and outlet axial extension lines of the banana bend dust collector have an included angle to make the airflow direction turn 180°.

[0013] Further, the water-cooled chain conveyor is connected to a dust discharging pipe, and the dust discharging pipe is provided with a pneumatic three-way discharge valve, a normal pneumatic double flap valve and an emergency pneumatic double flap valve.

[0014] The water-cooled chain conveyor discharges dust to the intermediate ash bin through the pneumatic three-way discharge valve, the normal pneumatic double flap valve and the bucket elevator, and the intermediate ash bin feeds the dust to the converter.

[0015] The water-cooled chain conveyor discharges dust to the coarse ash bin through the pneumatic three-way discharge valve, the emergency pneumatic double flap valve, and the coarse ash bin transports the coarse ash by a vacuum suction truck or transports the coarse ash to the intermediate ash bin by a bin pump.

[0016] Further, the cyclone heat recovery device is provided with a cyclone device and a heat recovery device, and the raw coal gas can effectively separate coarse particles and dust after cyclone and enhance heat exchange. The outlet of the cyclone heat recovery device is connected to a raw coal gas pipe.

[0017] Further, the high-temperature-resistant explosion-proof super-clean dust collector can be used in combination of two or more, the inlets of the dust collectors are connected to a raw coal gas pipe, the gas outlets of the dust collectors are connected to a clean gas pipe, the dust outlets of the dust collectors are connected to a fine ash bin through a dust collecting pipe, each dust collector is provided with an explosion relief valve, a rapping device, a heating coil and a heat preservation structure, and each high-temperature-resistant explosion-proof super-clean dust collector is connected to a cooling replacement fan through a pipeline.

[0018] Further, a silencer is arranged on the pipeline between the coal gas axial flow fan and the coal gas washing dehydrator, clean coal gas is sent to the coal gas switching station after being washed and cooled by the coal gas axial flow fan, the silencer and the coal gas washing dehydrator, a recovery cup valve is arranged on the pipeline of qualified coal gas output by the coal gas switching station, and a diffusion cup valve is arranged on the pipeline of unqualified coal gas output by the coal gas switching station.

[0019] Further, the nitrogen injection pipe and the purge pipe are arranged on one side of the diffusion chimney, the medium transported by the nitrogen injection pipe is medium-pressure nitrogen with a pressure of greater than or equal to 1.2 MPa, and the medium transported by the purge pipe is low-pressure nitrogen or saturated steam with a pressure of greater than or equal to 0.6 MPa.

[0020] The super-clean converter one-time dry dust removal system has the following beneficial effects:

[0021] 1. The utility model discloses cancel the traditional evaporation cold water spray, solve the stubborn disease of easy scale formation of evaporation cold, converter gas waste heat is fully recovered, and the steam recovery amount of ton steel is increased by more than 50 kg, and the system is more energy-saving.

[0022] 2. After the high-temperature explosion-proof super-clean dust remover process is used, the outlet concentration of the high-temperature explosion-proof super-clean dust remover can be maintained at 5 mg / Nm 3 The system is more environmentally friendly.

[0023] 3. The utility model not only solves the problem that high-quality heat is not recovered, but also solves the problem that the diffusion chimney emission exceeds the standard caused by the maintenance of the electrostatic precipitator, and also solves the problem that the emission concentration of the diffusion chimney outlet fluctuates greatly, and is especially suitable for converter one-time flue gas dry dust removal projects and has wide application prospect. DETAILED DESCRIPTION

[0024] Figure 1 It is a structural schematic diagram of an embodiment of the utility model.

[0025] Figure 2 It is Figure 1 A zoomed-in view of the middle A.

[0026] Figure 3 It is Figure 1 A zoomed-in view of the middle B.

[0027] Figure 4 It is Figure 1 A zoomed-in view of the middle C. DETAILED DESCRIPTION

[0028] The utility model will be further described below in combination with the drawings:

[0029] Embodiment: please refer to Figures 1 to 4A primary dry dust removal system for an ultra-clean converter includes a high-efficiency heat exchanger 3, a banana-bend separator 4, a cyclone heat recovery device 5, a water-cooled chain conveyor 6, a raw coal gas pipe 15, an electrostatic precipitator 16, a high-temperature resistant explosion-proof ultra-clean dust collector 23, a cooling and displacement fan 26, a clean coal gas pipe 27, a coal gas axial flow fan 28, and a coal gas scrubbing and dehydrating device 30.

[0030] The inlet of the high-efficiency heat exchanger 3 is connected to the converter 1 through the vaporization cooling flue 2. The raw coal gas of the converter 1 enters the high-efficiency heat exchanger 3 for heat exchange and recovery. A banana-bend dust collector 4 is provided between the high-efficiency heat exchanger 3 and the cyclone heat recovery device 5. A water-cooled chain conveyor 6 is provided at the bottom of the banana-bend dust collector 4 to collect coarse ash and transport it out.

[0031] The output end of the cyclone heat recovery device 5 is connected to the electrostatic precipitator 16 and / or the high-temperature explosion-proof ultra-clean dust collector 23 via the raw coal gas pipe 15.

[0032] The output end of the high-temperature explosion-proof ultra-clean dust collector 23 is connected to the clean gas pipe 27. The gas from the clean gas pipe 27 is washed and cooled by the gas axial flow fan 28 and the gas cooling dehydrator 30 before being sent to the gas switching station. Gas that passes the test is sent to the gas holder 32; unqualified gas is sent to the venting chimney 34 for ignition and venting. The converter 1, vaporization cooling flue 2, and gas holder 32 involved are not part of the dry dust removal system. The converter is defined as: a decarburization converter, a dephosphorization converter, a vanadium extraction converter, a lava homogenization furnace, or a stainless steel converter. This utility model's ultra-clean converter primary dry dust removal system is suitable for converters ranging from 50t to 400t.

[0033] The specific structure of this utility model's ultra-clean converter primary dry dust removal system includes: 3. High-efficiency heat exchanger; 4. Banana bend separator; 5. Cyclone heat recovery device; 6. Water-cooled chain conveyor; 7. Pneumatic three-way unloading valve; 8. Normal pneumatic double-layer flap valve; 9. Normal ash discharge pipe; 10. Bucket elevator; 11. Intermediate ash silo; 12. Emergency pneumatic double-layer flap valve; 13. Emergency ash discharge pipe; 14. Coarse ash silo; 15. Raw coal gas pipe; 16. Electrostatic precipitator; 17. First metal hard-seal butterfly valve. First explosion-proof spectacle valve 18, second metal hard-seal butterfly valve 19, second explosion-proof spectacle valve 20, third metal hard-seal butterfly valve 21, third explosion-proof spectacle valve 22, high-temperature explosion-proof ultra-clean dust collector 23, silo pump 24, fine ash silo 25, cooling displacement fan 26, clean gas pipe 27, gas axial flow fan 28, silencer 29, gas scrubber dehydrator 30, recovery cup valve 31, venting cup valve 33, venting chimney 34, nitrogen ejector pipe 35, and purge pipe 36.

[0034] Converter 1 and high efficiency heat exchanger 3 are connected by vaporization cooling flue 2, and banana bend separator 4 is arranged between high efficiency heat exchanger 3 and cyclone heat recovery device 5; heat exchange dense tube is arranged in high efficiency heat exchanger 3, high-quality heat in converter gas is taken away through heat exchange, thereby reducing the temperature of converter gas;

[0035] Banana bend separator 4 is provided with multiple layers of baffles, which can increase the residence time of dust-containing converter gas in banana bend separator 4 and improve the dust removal efficiency; water-cooled chain conveyor 6 is arranged at the bottom of banana bend separator 4 to convey the captured coarse ash; the material of banana bend separator 4 is stainless steel or boiler steel or Q345R or other functional materials, and the baffles of banana bend separator 4 can be used in two layers or multiple layers.

[0036] Cyclone device and heat recovery device are arranged in cyclone heat recovery device 5; after the cyclone, the raw gas can effectively separate the coarse particle dust and strengthen the heat exchange, which is beneficial to heat recovery.

[0037] Pneumatic three-way discharge valve 7, normal pneumatic double flap valve 8 and emergency pneumatic double flap valve 12 are arranged on the ash discharge pipe of water-cooled chain conveyor 6;

[0038] Water-cooled chain conveyor 6 normally discharges ash to intermediate ash bin 11 through pneumatic three-way discharge valve 7, normal pneumatic double flap valve 8 and bucket elevator 10, and intermediate ash bin 11 feeds into converter 1;

[0039] Water-cooled chain conveyor 6 discharges ash to coarse ash bin 14 in an emergency through pneumatic three-way discharge valve 7 and emergency pneumatic double flap valve 12, and coarse ash bin 14 transports coarse ash to intermediate ash bin 11 through vacuum suction truck or pneumatic conveying through bin pump;

[0040] Cyclone heat recovery device 5 and electrostatic precipitator 16 are connected through raw gas pipe 15;

[0041] First metal hard seal butterfly valve 17 and first explosion-proof mirror valve 18 are arranged at the inlet main pipe of electrostatic precipitator 16, and second metal hard seal butterfly valve 19 and second explosion-proof mirror valve 20 are arranged at the outlet main pipe;

[0042] Third metal hard seal butterfly valve 21 and third explosion-proof mirror valve 22 are arranged at the inlet main pipe of high-temperature explosion-proof super-clean dust collector 23;

[0043] High-temperature explosion-proof super-clean dust collector 23 is provided with a venting valve, a rapping device, a heating coil and a heat preservation structure, and the heat preservation structure can be a heat preservation layer made of heat preservation material;

[0044] High-temperature explosion-proof super-clean dust collector 23 is provided with cooling replacement fan 26; once the dust collector is overhauled, after the gas is replaced by nitrogen, cooling replacement fan 26 is started to blow air into the dust collector cylinder, which plays a role of cooling and ventilation;

[0045] The high-temperature-resistant explosion-proof super-clean dust collector 23 pneumatically transports the collected fine ash into the fine ash bin 25 through the bin pump 24; the fine ash bin 25 is provided with a vacuum suction and discharge tank truck interface;

[0046] The outlet of the high-temperature-resistant explosion-proof super-clean dust collector 23 is provided with a clean gas pipe 27; the clean gas passes through a gas axial flow fan 28 and a silencer 29, is washed and cooled by a gas washing and dewatering device 30, and is then sent to a gas switching station; the qualified gas passes through a recovery cup valve 31 and is sent to a gas tank 32; the unqualified gas passes through a diffusing cup valve 33 and is sent to a diffusing chimney 34 for ignition and diffusion;

[0047] The electrostatic precipitator 16 and the high-temperature-resistant explosion-proof super-clean dust collector 23 can work in series, or the high-temperature-resistant explosion-proof super-clean dust collector can work alone after the first metal hard-sealed butterfly valve 17, the first explosion-proof mirror valve 18, the second metal hard-sealed butterfly valve 19 and the second explosion-proof mirror valve 20 are closed and the third metal hard-sealed butterfly valve 21 and the third explosion-proof mirror valve 22 are opened. After the electrostatic precipitator and the high-temperature-resistant explosion-proof super-clean dust collector are used in combination, a dust removal device is added at the outlet of the electrostatic precipitator, the dust from the electrostatic precipitator is captured by the high-temperature-resistant explosion-proof super-clean dust collector, and thus the corresponding defects mentioned in the background art are overcome.

[0048] The diffusing chimney 34 is provided with a nitrogen injection pipe 35 and a purging pipe 36.

[0049] The process flow of the super-clean converter one-stage dry dust removal system in the utility model is as follows:

[0050] Converter 1→ vaporization cooling flue 2→ high-efficiency heat exchanger 3→ banana bend separator 4→ cyclone heat recovery device 5→ raw gas pipe 15→ electrostatic precipitator 16 / high-temperature-resistant explosion-proof super-clean dust collector 23→ clean gas pipe 27→ gas axial flow fan 28→ silencer 29→ gas washing and dewatering device 30→ recovery cup valve 31 / diffusing cup valve 33→ / gas tank 32 diffusing chimney 34.

[0051] The outlet temperature of the reinforced vaporization cooling flue 2 is 750-850℃ (generally 800℃), the raw gas is subjected to high-efficiency heat exchange by the high-efficiency heat exchanger 3, the high-quality heat in the raw gas is recovered with high efficiency, and the temperature is reduced to 600℃ to enter the banana bend separator 4.

[0052] When the dust-containing raw gas passes through the banana bend separator 4, it first passes through multiple baffle collisions, and due to the flow direction change of 180°, 35%-45% (generally 40%) of the coarse particle dust is captured in the banana bend separator 4 under the action of gravity and centrifugal force and falls into the water-cooled chain conveyor 6.

[0053] The water-cooled chain conveyor 6 is horizontally arranged and is linked with the converter 1 process, and is periodically operated during smelting.

[0054] Normally, the coarse ash collected by the water-cooled chain conveyor 6 is discharged through the pneumatic three-way discharge valve 7 and the normal pneumatic double-layer flap valve 8 into the normal ash discharge pipe 9, and then is discharged by the bucket elevator 10 into the intermediate ash bin 11.

[0055] When the bucket elevator 10 is under maintenance, the coarse ash collected by the water-cooled chain conveyor 6 is discharged through the pneumatic three-way discharge valve 7 and the emergency pneumatic double-layer flap valve 12 into the emergency ash discharge pipe 13, and then is discharged into the coarse ash bin 14.

[0056] The explosion vent of the high-temperature explosion-proof super-clean dust collector 23 is provided with three levels of explosion venting.

[0057] The qualified converter gas enters the gas washing and dewatering device 30, and after being cooled by saturated water spraying, the temperature is reduced from 150 DEG C to below 70 DEG C, so that the gas tank 32 can store more converter gas.

[0058] In the system, once the system is powered off or the gas axial flow fan 28 fails, the pneumatic cut-off valve on the nitrogen injection pipe 35 is opened, nitrogen injection is performed for 15S, and the safety of the system is ensured. In the system, once the system is powered off or the gas axial flow fan 28 fails, the pneumatic cut-off valve on the nitrogen injection pipe 35 is opened, nitrogen injection is performed for 15S, and the safety of the system is ensured. In the system, once the system is powered off or the gas axial flow fan 28 fails, the pneumatic cut-off valve on the nitrogen injection pipe 35 is opened, nitrogen injection is performed for 15S, and the safety of the system is ensured. In the system, once the system is powered off or the gas axial flow fan 28 fails, the pneumatic cut-off valve on the nitrogen injection pipe 35 is opened, nitrogen injection is performed for 15S, and the safety of the system is ensured. 3 .

[0059] In an embodiment of the system, the medium delivered by the blowing pipe 36 is low-pressure nitrogen or saturated steam, and the pressure of the low-pressure nitrogen or saturated steam is greater than or equal to 0.6MPa.

[0060] In an embodiment of the system, the medium delivered by the blowing pipe 36 is low-pressure nitrogen or saturated steam, and the pressure of the low-pressure nitrogen or saturated steam is greater than or equal to 0.6MPa.

[0061] The above-described embodiments are merely illustrative for the application and any modification, variation, or improvement made by those skilled in the art based on the teachings of the application shall fall within the scope of the patent application.

Claims

1. A primary dry dust removal system for an ultra-clean converter, characterized in that: This includes high-efficiency heat exchangers, banana-bend separators, cyclone heat recovery devices, water-cooled chain conveyors, raw coal gas pipes, electrostatic precipitators, high-temperature explosion-proof ultra-clean dust collectors, cooling and displacement fans, clean coal gas pipes, coal gas axial flow fans, and coal gas scrubbing and dehydrating devices. The inlet of the high-efficiency heat exchanger is connected to the converter through a vaporization cooling flue. The raw coal gas from the converter enters the high-efficiency heat exchanger for heat exchange and recovery. A banana-bend dust collector is installed between the high-efficiency heat exchanger and the cyclone heat recovery device. A water-cooled chain conveyor is installed at the bottom of the banana-bend dust collector to collect coarse ash and transport it out. The output end of the cyclone heat recovery device is connected to an electrostatic precipitator and / or a high-temperature explosion-proof ultra-clean dust collector via a raw coal gas pipe. The output end of the high-temperature explosion-proof ultra-clean dust collector is connected to the clean gas pipe. The gas in the clean gas pipe is washed and cooled by the gas axial flow fan and the gas cooling dehydrator before being sent to the gas switching station. The qualified gas is sent to the gas holder; the unqualified gas is sent to the venting chimney for ignition and venting.

2. The ultra-clean converter primary dry dust removal system according to claim 1, characterized in that: Electrostatic precipitators and high-temperature explosion-proof ultra-clean dust collectors can be connected in series or the high-temperature explosion-proof ultra-clean dust collector can work alone. The electrostatic precipitator inlet main pipe is equipped with a first metal hard-seal butterfly valve and a first explosion-proof spectacle valve, and the outlet main pipe is equipped with a second metal hard-seal butterfly valve and a second explosion-proof spectacle valve. The inlet main pipe of the high-temperature resistant explosion-proof ultra-clean dust collector is equipped with a third metal hard-seal butterfly valve and a third explosion-proof spectacle valve.

3. The ultra-clean converter primary dry dust removal system according to claim 1, characterized in that: The outlet temperature of the vaporization cooling flue is 750℃~850℃. After the raw coal gas passes through the high-efficiency heat exchanger, the high-quality heat in the raw coal gas is efficiently recovered and the temperature drops to 600℃ before entering the banana bend dust collector. The banana bend dust collector is equipped with multiple layers of baffles. The axial extension lines of the inlet and outlet of the banana bend dust collector have an angle that causes the airflow direction to turn 180°.

4. The ultra-clean converter primary dry dust removal system according to claim 1, characterized in that: The water-cooled chain conveyor is connected to the ash discharge pipe, which is equipped with a pneumatic three-way discharge valve, a normal pneumatic double-layer flap valve, and an emergency pneumatic double-layer flap valve. The water-cooled chain conveyor discharges ash normally to the intermediate ash silo via a pneumatic three-way unloading valve, a normal pneumatic double-layer flap valve, and a bucket elevator. The intermediate ash silo then feeds material into the converter. The water-cooled chain conveyor discharges ash to the coarse ash silo via a pneumatic three-way unloading valve and an emergency pneumatic double-layer flap valve. The coarse ash silo is then transported out by a vacuum suction truck or pneumatically conveyed to the intermediate ash silo by a silo pump.

5. The ultra-clean converter primary dry dust removal system according to claim 1, characterized in that: The cyclone heat recovery device is equipped with a cyclone device and a heat recovery device. After passing through the cyclone, the raw coal gas can effectively separate coarse dust particles and enhance heat exchange. The outlet of the cyclone heat recovery device is connected to the raw coal gas pipe.

6. The ultra-clean converter primary dry dust removal system according to claim 1, characterized in that: High-temperature explosion-proof ultra-clean dust collectors can be used in combination of two or more. The inlet of each dust collector is connected to the raw coal gas pipe, the outlet of each dust collector is connected to the clean coal gas pipe, and the ash outlet of each dust collector is transported to the fine ash bin through the ash collection pipe. Each dust collector is equipped with an explosion relief valve, a vibrator, a heating coil and a heat preservation structure. Each high-temperature explosion-proof ultra-clean dust collector is connected to a cooling and displacement fan through a pipeline.

7. The ultra-clean converter primary dry dust removal system according to claim 1, characterized in that: A silencer is installed on the pipeline between the gas axial flow fan and the gas scrubbing and dehydrating device. After the clean gas is washed and cooled by the gas axial flow fan, the silencer and the gas scrubbing and dehydrating device, it is sent to the gas switching station. The qualified gas output from the gas switching station is equipped with a recovery cup valve, and the unqualified gas output from the gas switching station is equipped with a vent cup valve.

8. The ultra-clean converter primary dry dust removal system according to any one of claims 1 to 7, characterized in that: A nitrogen ejector pipe and a purge pipe are installed on one side of the venting chimney. The nitrogen ejector pipe delivers medium-pressure nitrogen at a pressure ≥1.2MPa, while the purge pipe delivers low-pressure nitrogen or saturated steam at a pressure ≥0.6MPa.

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